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digitalmars.D - Found by Coverty in LibreOffice

reply "bearophile" <bearophileHUGS lycos.com> writes:
Some of the bugs that the static analysis tool Coverty has found 
in the C++ code of LibreOffice:

http://cgit.freedesktop.org/libreoffice/core/log/?qt=grep&q=coverity


Cases like this remind me that division operator shouldn't accept 
a divisor of generic integer/floating/multi-precision type, but a 
type that lacks a zero:

http://cgit.freedesktop.org/libreoffice/core/commit/?id=4a83b67e3c3dc8bceb6602ce155f2463f72f4855

http://cgit.freedesktop.org/libreoffice/core/commit/?id=7ca34b04c0915cb00345afa1ba7cfc736f82f9a1

http://cgit.freedesktop.org/libreoffice/core/commit/?id=c61b2066660fb0130f0b0f9f51b48e3799625b83

Bye,
bearophile
Nov 10 2014
parent reply Rikki Cattermole <alphaglosined gmail.com> writes:
On 10/11/2014 11:04 p.m., bearophile wrote:

 Some of the bugs that the static analysis tool Coverty has found in the
 C++ code of LibreOffice:

 http://cgit.freedesktop.org/libreoffice/core/log/?qt=grep&q=coverity


 Cases like this remind me that division operator shouldn't accept a
 divisor of generic integer/floating/multi-precision type, but a type
 that lacks a zero:

 http://cgit.freedesktop.org/libreoffice/core/commit/?id=4a83b67e3c3dc8bceb6602ce155f2463f72f4855


 http://cgit.freedesktop.org/libreoffice/core/commit/?id=7ca34b04c0915cb00345afa1ba7cfc736f82f9a1


 http://cgit.freedesktop.org/libreoffice/core/commit/?id=c61b2066660fb0130f0b0f9f51b48e3799625b83


 Bye,
 bearophile


Interesting.
Code like this could be rather interesting.

alias NonZero = AbituaryRestriction!("value == 0", "Value cannot be 0");
template AbituaryRestriction(string restriction, string reason) {
	struct AbituaryRestriction(T) {
		T value;
		alias value this;
	
		this(T value) {
			this.value = value;
		}
		
		invariant() {
			if (mixin(restriction)) {
				throw new Exception(reason);	
			}
		}
		
		void opAssign(float value) {
			this.value = value;	
		}
	}
}

void main() {
	NonZero!float ft = 0.5f;
	ft = 0;
}
Nov 10 2014
next sibling parent Rikki Cattermole <alphaglosined gmail.com> writes:
On 10/11/2014 11:23 p.m., Rikki Cattermole wrote:

 On 10/11/2014 11:04 p.m., bearophile wrote:

 Some of the bugs that the static analysis tool Coverty has found in the
 C++ code of LibreOffice:

 http://cgit.freedesktop.org/libreoffice/core/log/?qt=grep&q=coverity


 Cases like this remind me that division operator shouldn't accept a
 divisor of generic integer/floating/multi-precision type, but a type
 that lacks a zero:

 http://cgit.freedesktop.org/libreoffice/core/commit/?id=4a83b67e3c3dc8bceb6602ce155f2463f72f4855



 http://cgit.freedesktop.org/libreoffice/core/commit/?id=7ca34b04c0915cb00345afa1ba7cfc736f82f9a1



 http://cgit.freedesktop.org/libreoffice/core/commit/?id=c61b2066660fb0130f0b0f9f51b48e3799625b83



 Bye,
 bearophile


 Interesting.
 Code like this could be rather interesting.

 alias NonZero = AbituaryRestriction!("value == 0", "Value cannot be 0");
 template AbituaryRestriction(string restriction, string reason) {
      struct AbituaryRestriction(T) {
          T value;
          alias value this;

          this(T value) {
              this.value = value;
          }

          invariant() {
              if (mixin(restriction)) {
                  throw new Exception(reason);
              }
          }

          void opAssign(float value) {


Looks like I didn't quite catch all those float's during testing. Woops 
(should be T instead of float).


              this.value = value;
          }
      }
 }

 void main() {
      NonZero!float ft = 0.5f;
      ft = 0;
 }
Nov 10 2014
prev sibling next sibling parent "John Colvin" <john.loughran.colvin gmail.com> writes:
On Monday, 10 November 2014 at 10:23:09 UTC, Rikki Cattermole 
wrote:

 On 10/11/2014 11:04 p.m., bearophile wrote:

 Some of the bugs that the static analysis tool Coverty has 
 found in the
 C++ code of LibreOffice:

 http://cgit.freedesktop.org/libreoffice/core/log/?qt=grep&q=coverity


 Cases like this remind me that division operator shouldn't 
 accept a
 divisor of generic integer/floating/multi-precision type, but 
 a type
 that lacks a zero:

 http://cgit.freedesktop.org/libreoffice/core/commit/?id=4a83b67e3c3dc8bceb6602ce155f2463f72f4855


 http://cgit.freedesktop.org/libreoffice/core/commit/?id=7ca34b04c0915cb00345afa1ba7cfc736f82f9a1


 http://cgit.freedesktop.org/libreoffice/core/commit/?id=c61b2066660fb0130f0b0f9f51b48e3799625b83


 Bye,
 bearophile


 Interesting.
 Code like this could be rather interesting.

 alias NonZero = AbituaryRestriction!("value == 0", "Value 
 cannot be 0");
 template AbituaryRestriction(string restriction, string reason) 
 {
 	struct AbituaryRestriction(T) {
 		T value;
 		alias value this;
 	
 		this(T value) {
 			this.value = value;
 		}
 		
 		invariant() {
 			if (mixin(restriction)) {
 				throw new Exception(reason);	
 			}
 		}
 		
 		void opAssign(float value) {
 			this.value = value;	
 		}
 	}
 }

 void main() {
 	NonZero!float ft = 0.5f;
 	ft = 0;
 }


you mean arbitrary, right?
Nov 10 2014
prev sibling next sibling parent "bearophile" <bearophileHUGS lycos.com> writes:
Rikki Cattermole:


 Cases like this remind me that division operator shouldn't 
 accept a divisor of generic integer/floating/multi-precision
 type, but a type that lacks a zero:


 ...
 Interesting.
 Code like this could be rather interesting.


In an old language like Ada you have to use explicitly a type 
that doesn't contain a zero (like a 1..5 range, or a natural, 
etc). But in a more modern language you can use "flow typing" (as 
seen in the Whiley language and elsewhere), so code similar to 
this (in D-like language) compiles:


int foo(in uint x, in uint y) {
     if (y == 0)
         throw new Exception("Bad");
     else {
         static assert(is(typeof(y) == Natural));
         return x / y;
     }
}

In Whiley inside the else branch the _type_ of y is different.

Bye,
bearophile
Nov 10 2014
prev sibling parent "Meta" <jared771 gmail.com> writes:
You might find this interesting:

http://forum.dlang.org/post/mailman.43.1385384503.3242.digitalmars-d puremagic.com
Nov 10 2014